namespace StellaOps.Scanner.Benchmark.Metrics;

/// <summary>
/// Benchmark metrics for comparing scanner accuracy.
/// </summary>
public sealed record BenchmarkMetrics
{
    /// <summary>
    /// Number of true positive findings.
    /// </summary>
    public required int TruePositives { get; init; }

    /// <summary>
    /// Number of false positive findings.
    /// </summary>
    public required int FalsePositives { get; init; }

    /// <summary>
    /// Number of true negative findings.
    /// </summary>
    public required int TrueNegatives { get; init; }

    /// <summary>
    /// Number of false negative findings (missed vulnerabilities).
    /// </summary>
    public required int FalseNegatives { get; init; }

    /// <summary>
    /// Precision = TP / (TP + FP).
    /// </summary>
    public double Precision => TruePositives + FalsePositives > 0
        ? (double)TruePositives / (TruePositives + FalsePositives)
        : 0;

    /// <summary>
    /// Recall = TP / (TP + FN).
    /// </summary>
    public double Recall => TruePositives + FalseNegatives > 0
        ? (double)TruePositives / (TruePositives + FalseNegatives)
        : 0;

    /// <summary>
    /// F1 Score = 2 * (Precision * Recall) / (Precision + Recall).
    /// </summary>
    public double F1Score => Precision + Recall > 0
        ? 2 * (Precision * Recall) / (Precision + Recall)
        : 0;

    /// <summary>
    /// Accuracy = (TP + TN) / (TP + TN + FP + FN).
    /// </summary>
    public double Accuracy
    {
        get
        {
            var total = TruePositives + TrueNegatives + FalsePositives + FalseNegatives;
            return total > 0 ? (double)(TruePositives + TrueNegatives) / total : 0;
        }
    }

    /// <summary>
    /// The scanner tool name.
    /// </summary>
    public required string ToolName { get; init; }

    /// <summary>
    /// The image reference that was scanned.
    /// </summary>
    public string? ImageRef { get; init; }

    /// <summary>
    /// Timestamp when the benchmark was run.
    /// </summary>
    public required DateTimeOffset Timestamp { get; init; }
}

/// <summary>
/// Aggregated metrics across multiple images.
/// </summary>
public sealed record AggregatedMetrics
{
    /// <summary>
    /// The scanner tool name.
    /// </summary>
    public required string ToolName { get; init; }

    /// <summary>
    /// Total images scanned.
    /// </summary>
    public required int TotalImages { get; init; }

    /// <summary>
    /// Sum of true positives across all images.
    /// </summary>
    public required int TotalTruePositives { get; init; }

    /// <summary>
    /// Sum of false positives across all images.
    /// </summary>
    public required int TotalFalsePositives { get; init; }

    /// <summary>
    /// Sum of true negatives across all images.
    /// </summary>
    public required int TotalTrueNegatives { get; init; }

    /// <summary>
    /// Sum of false negatives across all images.
    /// </summary>
    public required int TotalFalseNegatives { get; init; }

    /// <summary>
    /// Aggregate precision.
    /// </summary>
    public double Precision => TotalTruePositives + TotalFalsePositives > 0
        ? (double)TotalTruePositives / (TotalTruePositives + TotalFalsePositives)
        : 0;

    /// <summary>
    /// Aggregate recall.
    /// </summary>
    public double Recall => TotalTruePositives + TotalFalseNegatives > 0
        ? (double)TotalTruePositives / (TotalTruePositives + TotalFalseNegatives)
        : 0;

    /// <summary>
    /// Aggregate F1 score.
    /// </summary>
    public double F1Score => Precision + Recall > 0
        ? 2 * (Precision * Recall) / (Precision + Recall)
        : 0;

    /// <summary>
    /// Breakdown by severity.
    /// </summary>
    public IReadOnlyDictionary<string, BenchmarkMetrics>? BySeverity { get; init; }

    /// <summary>
    /// Breakdown by ecosystem.
    /// </summary>
    public IReadOnlyDictionary<string, BenchmarkMetrics>? ByEcosystem { get; init; }

    /// <summary>
    /// Individual image metrics.
    /// </summary>
    public IReadOnlyList<BenchmarkMetrics>? PerImageMetrics { get; init; }

    /// <summary>
    /// Timestamp when the aggregation was computed.
    /// </summary>
    public required DateTimeOffset Timestamp { get; init; }
}